A connection device of this type is known from EP 1 845 299 B1. It comprises a housing into which the insertion section is able to be inserted. The known connection device has, in addition, a blocking element by which the insertion section, inserted into the housing, is able to be locked in the housing. For locking the insertion section in the housing, the blocking element engages into the outer groove of the insertion section and into an annular inner groove formed in the housing. Through a housing opening, the blocking element is able to be withdrawn substantially tangentially to the grooves from the latter. In addition, the blocking element is able to be pre-fitted in the inner groove and in the pre-fitted state permits, with elastic deflection, the inserting of the insertion section into the housing, wherein then the blocking element engages into the outer groove. Furthermore, in the connection device, the blocking element is secured in the pre-fitted state on the housing against a displacement in the peripheral direction.
In the known connection device, the blocking element is situated in the pre-fitted state largely within the outer periphery of the housing. The securing of the blocking element against displacement takes place exclusively within the outer periphery of the housing, and namely in the region of the housing opening.
Further connection devices which comprise a housing, an insertion section and a blocking element are known for example from U.S. Pat. No. 6,179,347 B1 and from U.S. Pat. No. 3,606,402.